// 头部特效
export const useAnimationInit = () => {
    const state = reactive({
        scrollHeight: 0,
    })

    const handleScrollHeight = () => {
        state.scrollHeight = window.scrollY * 0.05
    }

    onMounted(() => {
        const canvas = document.getElementsByTagName("canvas")[0];
        canvas.width = canvas.clientWidth;
        canvas.height = canvas.clientHeight;

        let config = {
            TEXTURE_DOWNSAMPLE: 1,
            DENSITY_DISSIPATION: 0.98,
            VELOCITY_DISSIPATION: 0.99,
            PRESSURE_DISSIPATION: 0.8,
            PRESSURE_ITERATIONS: 25,
            CURL: 28,
            SPLAT_RADIUS: 0.004,
        };

        let pointers = [];
        let splatStack = [];

        const { gl, ext } = getWebGLContext(canvas);

        function getWebGLContext(canvas) {
            const params = {
                alpha: false,
                depth: false,
                stencil: false,
                antialias: false,
            };

            let gl = canvas.getContext("webgl2", params);
            const isWebGL2 = !!gl;
            if (!isWebGL2)
                gl =
                    canvas.getContext("webgl", params) ||
                    canvas.getContext("experimental-webgl", params);

            let halfFloat;
            let supportLinearFiltering;
            if (isWebGL2) {
                gl.getExtension("EXT_color_buffer_float");
                supportLinearFiltering = gl.getExtension("OES_texture_float_linear");
            } else {
                halfFloat = gl.getExtension("OES_texture_half_float");
                supportLinearFiltering = gl.getExtension("OES_texture_half_float_linear");
            }

            gl.clearColor(1.0, 1.0, 1.0, 1.0);

            const halfFloatTexType = isWebGL2
                ? gl.HALF_FLOAT
                : halfFloat.HALF_FLOAT_OES;
            let formatRGBA;
            let formatRG;
            let formatR;

            if (isWebGL2) {
                formatRGBA = getSupportedFormat(
                    gl,
                    gl.RGBA16F,
                    gl.RGBA,
                    halfFloatTexType
                );
                formatRG = getSupportedFormat(gl, gl.RG16F, gl.RG, halfFloatTexType);
                formatR = getSupportedFormat(gl, gl.R16F, gl.RED, halfFloatTexType);
            } else {
                formatRGBA = getSupportedFormat(gl, gl.RGBA, gl.RGBA, halfFloatTexType);
                formatRG = getSupportedFormat(gl, gl.RGBA, gl.RGBA, halfFloatTexType);
                formatR = getSupportedFormat(gl, gl.RGBA, gl.RGBA, halfFloatTexType);
            }

            return {
                gl,
                ext: {
                    formatRGBA,
                    formatRG,
                    formatR,
                    halfFloatTexType,
                    supportLinearFiltering,
                },
            };
        }

        function getSupportedFormat(
            gl,
            internalFormat,
            format,
            type
        ) {
            if (!supportRenderTextureFormat(gl, internalFormat, format, type)) {
                switch (internalFormat) {
                    case gl.R16F:
                        return getSupportedFormat(gl, gl.RG16F, gl.RG, type);
                    case gl.RG16F:
                        return getSupportedFormat(gl, gl.RGBA16F, gl.RGBA, type);
                    default:
                        return null;
                }
            }

            return {
                internalFormat,
                format,
            };
        }

        function supportRenderTextureFormat(
            gl,
            internalFormat,
            format,
            type
        ) {
            let texture = gl.createTexture();
            gl.bindTexture(gl.TEXTURE_2D, texture);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
            gl.texImage2D(
                gl.TEXTURE_2D,
                0,
                internalFormat,
                4,
                4,
                0,
                format,
                type,
                null
            );

            let fbo = gl.createFramebuffer();
            gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
            gl.framebufferTexture2D(
                gl.FRAMEBUFFER,
                gl.COLOR_ATTACHMENT0,
                gl.TEXTURE_2D,
                texture,
                0
            );

            const status = gl.checkFramebufferStatus(gl.FRAMEBUFFER);
            if (status != gl.FRAMEBUFFER_COMPLETE) return false;
            return true;
        }

        function pointerPrototype() {
            this.id = -1;
            this.x = 0;
            this.y = 0;
            this.dx = 0;
            this.dy = 0;
            this.down = false;
            this.moved = false;
            this.color = [30, 0, 300];
        }

        pointers.push(new pointerPrototype());

        class GLProgram {
            constructor(vertexShader, fragmentShader) {
                this.uniforms = {};
                this.program = gl.createProgram();

                gl.attachShader(this.program, vertexShader);
                gl.attachShader(this.program, fragmentShader);
                gl.linkProgram(this.program);

                if (!gl.getProgramParameter(this.program, gl.LINK_STATUS))
                    throw gl.getProgramInfoLog(this.program);

                const uniformCount = gl.getProgramParameter(
                    this.program,
                    gl.ACTIVE_UNIFORMS
                );
                for (let i = 0; i < uniformCount; i++) {
                    const uniformName = gl.getActiveUniform(this.program, i).name;
                    this.uniforms[uniformName] = gl.getUniformLocation(
                        this.program,
                        uniformName
                    );
                }
            }

            bind() {
                gl.useProgram(this.program);
            }
        }

        function compileShader(type, source) {
            const shader = gl.createShader(type);
            gl.shaderSource(shader, source);
            gl.compileShader(shader);

            if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS))
                throw gl.getShaderInfoLog(shader);

            return shader;
        }

        //********定义着色器程序  顶点着色器代码**********
        const baseVertexShader = compileShader(
            gl.VERTEX_SHADER,
            `
          precision highp float;
          precision mediump sampler2D;
      
          attribute vec2 aPosition;
          varying vec2 vUv;
          varying vec2 vL;
          varying vec2 vR;
          varying vec2 vT;
          varying vec2 vB;
          uniform vec2 texelSize;
      
          void main () {
              vUv = aPosition * 0.5 + 0.5;
              vL = vUv - vec2(texelSize.x, 0.0);
              vR = vUv + vec2(texelSize.x, 0.0);
              vT = vUv + vec2(0.0, texelSize.y);
              vB = vUv - vec2(0.0, texelSize.y);
              gl_Position = vec4(aPosition, 0.0, 1.0);
          }
      `
        );
        //定义着色器程序  // 清除着色器代码
        const clearShader = compileShader(
            gl.FRAGMENT_SHADER,
            `
          precision highp float;
          precision mediump sampler2D;
      
          varying vec2 vUv;
          uniform sampler2D uTexture;
          uniform float value;
      
          void main () {
              gl_FragColor = value * texture2D(uTexture, vUv);
          }
      `
        );

        const displayShader = compileShader(
            gl.FRAGMENT_SHADER,
            `
          precision highp float;
          precision mediump sampler2D;
      
          varying vec2 vUv;
          uniform sampler2D uTexture;
      
          void main () {
             gl_FragColor = texture2D(uTexture, vUv);
              //  gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
          }
      `
        );

        const splatShader = compileShader(
            gl.FRAGMENT_SHADER,
            `
          precision highp float;
          precision mediump sampler2D;
      
          varying vec2 vUv;
          uniform sampler2D uTarget;
          uniform float aspectRatio;
          uniform vec3 color;
          uniform vec2 point;
          uniform float radius;
      
          void main () {
              vec2 p = vUv - point.xy;
              p.x *= aspectRatio;
              vec3 splat = exp(-dot(p, p) / radius) * color;
              vec3 base = texture2D(uTarget, vUv).xyz;
              gl_FragColor = vec4(base + splat, 1.0);
          }
      `
        );

        const advectionManualFilteringShader = compileShader(
            gl.FRAGMENT_SHADER,
            `
          precision highp float;
          precision mediump sampler2D;
      
          varying vec2 vUv;
          uniform sampler2D uVelocity;
          uniform sampler2D uSource;
          uniform vec2 texelSize;
          uniform float dt;
          uniform float dissipation;
      
          vec4 bilerp (in sampler2D sam, in vec2 p) {
              vec4 st;
              st.xy = floor(p - 0.5) + 0.5;
              st.zw = st.xy + 1.0;
              vec4 uv = st * texelSize.xyxy;
              vec4 a = texture2D(sam, uv.xy);
              vec4 b = texture2D(sam, uv.zy);
              vec4 c = texture2D(sam, uv.xw);
              vec4 d = texture2D(sam, uv.zw);
              vec2 f = p - st.xy;
              return mix(mix(a, b, f.x), mix(c, d, f.x), f.y);
          }
      
          void main () {
              vec2 coord = gl_FragCoord.xy - dt * texture2D(uVelocity, vUv).xy;
              gl_FragColor = dissipation * bilerp(uSource, coord);
              gl_FragColor.a = 1.0;
          }
      `
        );

        const advectionShader = compileShader(
            gl.FRAGMENT_SHADER,
            `
          precision highp float;
          precision mediump sampler2D;
      
          varying vec2 vUv;
          uniform sampler2D uVelocity;
          uniform sampler2D uSource;
          uniform vec2 texelSize;
          uniform float dt;
          uniform float dissipation;
      
          void main () {
              vec2 coord = vUv - dt * texture2D(uVelocity, vUv).xy * texelSize;
              gl_FragColor = dissipation * texture2D(uSource, coord);
              gl_FragColor.a = 1.0;
          }
      `
        );

        const divergenceShader = compileShader(
            gl.FRAGMENT_SHADER,
            `
          precision highp float;
          precision mediump sampler2D;
      
          varying vec2 vUv;
          varying vec2 vL;
          varying vec2 vR;
          varying vec2 vT;
          varying vec2 vB;
          uniform sampler2D uVelocity;
      
          vec2 sampleVelocity (in vec2 uv) {
              vec2 multiplier = vec2(1.0, 1.0);
              if (uv.x < 0.0) { uv.x = 0.0; multiplier.x = -1.0; }
              if (uv.x > 1.0) { uv.x = 1.0; multiplier.x = -1.0; }
              if (uv.y < 0.0) { uv.y = 0.0; multiplier.y = -1.0; }
              if (uv.y > 1.0) { uv.y = 1.0; multiplier.y = -1.0; }
              return multiplier * texture2D(uVelocity, uv).xy;
          }
      
          void main () {
              float L = sampleVelocity(vL).x;
              float R = sampleVelocity(vR).x;
              float T = sampleVelocity(vT).y;
              float B = sampleVelocity(vB).y;
              float div = 0.5 * (R - L + T - B);
              gl_FragColor = vec4(div, 0.0, 0.0, 1.0);
          }
      `
        );

        const curlShader = compileShader(
            gl.FRAGMENT_SHADER,
            `
          precision highp float;
          precision mediump sampler2D;
      
          varying vec2 vUv;
          varying vec2 vL;
          varying vec2 vR;
          varying vec2 vT;
          varying vec2 vB;
          uniform sampler2D uVelocity;
      
          void main () {
              float L = texture2D(uVelocity, vL).y;
              float R = texture2D(uVelocity, vR).y;
              float T = texture2D(uVelocity, vT).x;
              float B = texture2D(uVelocity, vB).x;
              float vorticity = R - L - T + B;
              gl_FragColor = vec4(vorticity, 0.0, 0.0, 1.0);
          }
      `
        );

        const vorticityShader = compileShader(
            gl.FRAGMENT_SHADER,
            `
          precision highp float;
          precision mediump sampler2D;
      
          varying vec2 vUv;
          varying vec2 vT;
          varying vec2 vB;
          uniform sampler2D uVelocity;
          uniform sampler2D uCurl;
          uniform float curl;
          uniform float dt;
      
          void main () {
              float T = texture2D(uCurl, vT).x;
              float B = texture2D(uCurl, vB).x;
              float C = texture2D(uCurl, vUv).x;
              vec2 force = vec2(abs(T) - abs(B), 0.0);
              force *= 1.0 / length(force + 0.00001) * curl * C;
              vec2 vel = texture2D(uVelocity, vUv).xy;
              gl_FragColor = vec4(vel + force * dt, 0.0, 1.0);
          }
      `
        );

        const pressureShader = compileShader(
            gl.FRAGMENT_SHADER,
            `
          precision highp float;
          precision mediump sampler2D;
      
          varying vec2 vUv;
          varying vec2 vL;
          varying vec2 vR;
          varying vec2 vT;
          varying vec2 vB;
          uniform sampler2D uPressure;
          uniform sampler2D uDivergence;
      
          vec2 boundary (in vec2 uv) {
              uv = min(max(uv, 0.0), 1.0);
              return uv;
          }
      
          void main () {
              float L = texture2D(uPressure, boundary(vL)).x;
              float R = texture2D(uPressure, boundary(vR)).x;
              float T = texture2D(uPressure, boundary(vT)).x;
              float B = texture2D(uPressure, boundary(vB)).x;
              float C = texture2D(uPressure, vUv).x;
              float divergence = texture2D(uDivergence, vUv).x;
              float pressure = (L + R + B + T - divergence) * 0.25;
              gl_FragColor = vec4(pressure, 0.0, 0.0, 1.0);
          }
      `
        );

        const gradientSubtractShader = compileShader(
            gl.FRAGMENT_SHADER,
            `
          precision highp float;
          precision mediump sampler2D;
      
          varying vec2 vUv;
          varying vec2 vL;
          varying vec2 vR;
          varying vec2 vT;
          varying vec2 vB;
          uniform sampler2D uPressure;
          uniform sampler2D uVelocity;
      
          vec2 boundary (in vec2 uv) {
              uv = min(max(uv, 0.0), 1.0);
              return uv;
          }
      
          void main () {
              float L = texture2D(uPressure, boundary(vL)).x;
              float R = texture2D(uPressure, boundary(vR)).x;
              float T = texture2D(uPressure, boundary(vT)).x;
              float B = texture2D(uPressure, boundary(vB)).x;
              vec2 velocity = texture2D(uVelocity, vUv).xy;
              velocity.xy -= vec2(R - L, T - B);
              gl_FragColor = vec4(velocity, 0.0, 1.0);
          }
      `
        );
        //********定义着色器程序结束 **********

        // 初始化帧缓冲对象：
        let textureWidth;
        let textureHeight;
        let density;
        let velocity;
        let divergence;
        let curl;
        let pressure;
        initFramebuffers();

        // 创建着色器程序对象
        const clearProgram = new GLProgram(baseVertexShader, clearShader);
        const displayProgram = new GLProgram(baseVertexShader, displayShader);
        const splatProgram = new GLProgram(baseVertexShader, splatShader);
        const advectionProgram = new GLProgram(
            baseVertexShader,
            ext.supportLinearFiltering
                ? advectionShader
                : advectionManualFilteringShader
        );
        const divergenceProgram = new GLProgram(baseVertexShader, divergenceShader);
        const curlProgram = new GLProgram(baseVertexShader, curlShader);
        const vorticityProgram = new GLProgram(baseVertexShader, vorticityShader);
        const pressureProgram = new GLProgram(baseVertexShader, pressureShader);
        const gradienSubtractProgram = new GLProgram(
            baseVertexShader,
            gradientSubtractShader
        );

        function initFramebuffers() {
            textureWidth = gl.drawingBufferWidth >> config.TEXTURE_DOWNSAMPLE;
            textureHeight = gl.drawingBufferHeight >> config.TEXTURE_DOWNSAMPLE;

            const texType = ext.halfFloatTexType;
            const rgba = ext.formatRGBA;
            const rg = ext.formatRG;
            const r = ext.formatR;

            density = createDoubleFBO(
                2,
                textureWidth,
                textureHeight,
                rgba.internalFormat,
                rgba.format,
                texType,
                ext.supportLinearFiltering ? gl.LINEAR : gl.NEAREST
            );
            velocity = createDoubleFBO(
                0,
                textureWidth,
                textureHeight,
                rg.internalFormat,
                rg.format,
                texType,
                ext.supportLinearFiltering ? gl.LINEAR : gl.NEAREST
            );
            divergence = createFBO(
                4,
                textureWidth,
                textureHeight,
                r.internalFormat,
                r.format,
                texType,
                gl.NEAREST
            );
            curl = createFBO(
                5,
                textureWidth,
                textureHeight,
                r.internalFormat,
                r.format,
                texType,
                gl.NEAREST
            );
            pressure = createDoubleFBO(
                6,
                textureWidth,
                textureHeight,
                r.internalFormat,
                r.format,
                texType,
                gl.NEAREST
            );
        }

        // 定义和创建帧缓冲对象和纹理
        function createFBO(texId, w, h, internalFormat, format, type, param) {
            gl.activeTexture(gl.TEXTURE0 + texId);
            let texture = gl.createTexture();
            gl.bindTexture(gl.TEXTURE_2D, texture);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, param);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, param);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
            gl.texImage2D(
                gl.TEXTURE_2D,
                0,
                internalFormat,
                w,
                h,
                0,
                format,
                type,
                null
            );

            let fbo = gl.createFramebuffer();
            gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
            gl.framebufferTexture2D(
                gl.FRAMEBUFFER,
                gl.COLOR_ATTACHMENT0,
                gl.TEXTURE_2D,
                texture,
                0
            );
            gl.viewport(0, 0, w, h);
            gl.clear(gl.COLOR_BUFFER_BIT);

            return [texture, fbo, texId];
        }

        function createDoubleFBO(texId, w, h, internalFormat, format, type, param) {
            let fbo1 = createFBO(texId, w, h, internalFormat, format, type, param);
            let fbo2 = createFBO(texId + 1, w, h, internalFormat, format, type, param);

            return {
                get read() {
                    return fbo1;
                },
                get write() {
                    return fbo2;
                },
                swap() {
                    let temp = fbo1;
                    fbo1 = fbo2;
                    fbo2 = temp;
                },
            };
        }

        const blit = (() => {
            gl.bindBuffer(gl.ARRAY_BUFFER, gl.createBuffer());
            gl.bufferData(
                gl.ARRAY_BUFFER,
                new Float32Array([-1, -1, -1, 1, 1, 1, 1, -1]),
                gl.STATIC_DRAW
            );
            gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, gl.createBuffer());
            gl.bufferData(
                gl.ELEMENT_ARRAY_BUFFER,
                new Uint16Array([0, 1, 2, 0, 2, 3]),
                gl.STATIC_DRAW
            );
            gl.vertexAttribPointer(0, 2, gl.FLOAT, false, 0, 0);
            gl.enableVertexAttribArray(0);

            return (destination) => {
                gl.bindFramebuffer(gl.FRAMEBUFFER, destination);
                gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0);
            };
        })();

        let lastTime = Date.now();
        multipleSplats(parseInt(Math.random() * 20) + 5);
        update();

        // 主渲染循环和计算流体效果：
        function update() {
            resizeCanvas();

            const dt = Math.min((Date.now() - lastTime) / 1000, 0.016);
            lastTime = Date.now();

            gl.viewport(0, 0, textureWidth, textureHeight);

            if (splatStack.length > 0) multipleSplats(splatStack.pop());

            advectionProgram.bind();
            gl.uniform2f(
                advectionProgram.uniforms.texelSize,
                1.0 / textureWidth,
                1.0 / textureHeight
            );
            gl.uniform1i(advectionProgram.uniforms.uVelocity, velocity.read[2]);
            gl.uniform1i(advectionProgram.uniforms.uSource, velocity.read[2]);
            gl.uniform1f(advectionProgram.uniforms.dt, dt);
            gl.uniform1f(
                advectionProgram.uniforms.dissipation,
                config.VELOCITY_DISSIPATION
            );
            blit(velocity.write[1]);
            velocity.swap();

            gl.uniform1i(advectionProgram.uniforms.uVelocity, velocity.read[2]);
            gl.uniform1i(advectionProgram.uniforms.uSource, density.read[2]);
            gl.uniform1f(
                advectionProgram.uniforms.dissipation,
                config.DENSITY_DISSIPATION
            );
            blit(density.write[1]);
            density.swap();

            for (let i = 0; i < pointers.length; i++) {
                const pointer = pointers[i];
                if (pointer.moved) {
                    splat(pointer.x, pointer.y, pointer.dx, pointer.dy, pointer.color);
                    pointer.moved = false;
                }
            }

            curlProgram.bind();
            gl.uniform2f(
                curlProgram.uniforms.texelSize,
                1.0 / textureWidth,
                1.0 / textureHeight
            );
            gl.uniform1i(curlProgram.uniforms.uVelocity, velocity.read[2]);
            blit(curl[1]);

            vorticityProgram.bind();
            gl.uniform2f(
                vorticityProgram.uniforms.texelSize,
                1.0 / textureWidth,
                1.0 / textureHeight
            );
            gl.uniform1i(vorticityProgram.uniforms.uVelocity, velocity.read[2]);
            gl.uniform1i(vorticityProgram.uniforms.uCurl, curl[2]);
            gl.uniform1f(vorticityProgram.uniforms.curl, config.CURL);
            gl.uniform1f(vorticityProgram.uniforms.dt, dt);
            blit(velocity.write[1]);
            velocity.swap();

            divergenceProgram.bind();
            gl.uniform2f(
                divergenceProgram.uniforms.texelSize,
                1.0 / textureWidth,
                1.0 / textureHeight
            );
            gl.uniform1i(divergenceProgram.uniforms.uVelocity, velocity.read[2]);
            blit(divergence[1]);

            clearProgram.bind();
            let pressureTexId = pressure.read[2];
            gl.activeTexture(gl.TEXTURE0 + pressureTexId);
            gl.bindTexture(gl.TEXTURE_2D, pressure.read[0]);
            gl.uniform1i(clearProgram.uniforms.uTexture, pressureTexId);
            gl.uniform1f(clearProgram.uniforms.value, config.PRESSURE_DISSIPATION);
            blit(pressure.write[1]);
            pressure.swap();

            pressureProgram.bind();
            gl.uniform2f(
                pressureProgram.uniforms.texelSize,
                1.0 / textureWidth,
                1.0 / textureHeight
            );
            gl.uniform1i(pressureProgram.uniforms.uDivergence, divergence[2]);
            pressureTexId = pressure.read[2];
            gl.uniform1i(pressureProgram.uniforms.uPressure, pressureTexId);
            gl.activeTexture(gl.TEXTURE0 + pressureTexId);
            for (let i = 0; i < config.PRESSURE_ITERATIONS; i++) {
                gl.bindTexture(gl.TEXTURE_2D, pressure.read[0]);
                blit(pressure.write[1]);
                pressure.swap();
            }

            gradienSubtractProgram.bind();
            gl.uniform2f(
                gradienSubtractProgram.uniforms.texelSize,
                1.0 / textureWidth,
                1.0 / textureHeight
            );
            gl.uniform1i(gradienSubtractProgram.uniforms.uPressure, pressure.read[2]);
            gl.uniform1i(gradienSubtractProgram.uniforms.uVelocity, velocity.read[2]);
            blit(velocity.write[1]);
            velocity.swap();

            gl.viewport(0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);
            displayProgram.bind();
            gl.uniform1i(displayProgram.uniforms.uTexture, density.read[2]);
            blit(null);

            requestAnimationFrame(update);
        }

        function splat(x, y, dx, dy, color) {
            splatProgram.bind();
            gl.uniform1i(splatProgram.uniforms.uTarget, velocity.read[2]);
            gl.uniform1f(
                splatProgram.uniforms.aspectRatio,
                canvas.width / canvas.height
            );
            gl.uniform2f(
                splatProgram.uniforms.point,
                x / canvas.width,
                1.0 - y / canvas.height
            );
            gl.uniform3f(splatProgram.uniforms.color, dx, -dy, 1.0);
            gl.uniform1f(splatProgram.uniforms.radius, config.SPLAT_RADIUS);
            blit(velocity.write[1]);
            velocity.swap();

            gl.uniform1i(splatProgram.uniforms.uTarget, density.read[2]);
            gl.uniform3f(
                splatProgram.uniforms.color,
                color[0] * 0.3,
                color[1] * 0.3,
                color[2] * 0.3
            );
            blit(density.write[1]);
            density.swap();
        }

        function multipleSplats(amount) {
            for (let i = 0; i < amount; i++) {
                const color = [
                    Math.random() * 10,
                    Math.random() * 10,
                    Math.random() * 10,
                ];
                const x = canvas.width * Math.random();
                const y = canvas.height * Math.random();
                const dx = 1000 * (Math.random() - 0.5);
                const dy = 1000 * (Math.random() - 0.5);
                splat(x, y, dx, dy, color);
            }
        }

        function resizeCanvas() {
            if (
                canvas.width != canvas.clientWidth ||
                canvas.height != canvas.clientHeight
            ) {
                canvas.width = canvas.clientWidth;
                canvas.height = canvas.clientHeight;
                initFramebuffers();
            }
        }

        canvas.addEventListener("mousemove", (e) => {
            pointers[0].moved = pointers[0].down;
            pointers[0].dx = (e.offsetX - pointers[0].x) * 10.0;
            pointers[0].dy = (e.offsetY - pointers[0].y) * 10.0;
            pointers[0].x = e.offsetX;
            pointers[0].y = e.offsetY;
        });

        canvas.addEventListener(
            "touchmove",
            (e) => {
                e.preventDefault();
                const touches = e.targetTouches;
                for (let i = 0; i < touches.length; i++) {
                    let pointer = pointers[i];
                    pointer.moved = pointer.down;
                    pointer.dx = (touches[i].pageX - pointer.x) * 10.0;
                    pointer.dy = (touches[i].pageY - pointer.y) * 10.0;
                    pointer.x = touches[i].pageX;
                    pointer.y = touches[i].pageY;
                }
            },
            false
        );

        canvas.addEventListener("mousemove", () => {
            pointers[0].down = true;
            pointers[0].color = [
                Math.random() + 0.2,
                Math.random() + 0.2,
                Math.random() + 0.2,
            ];
        });

        canvas.addEventListener("touchstart", (e) => {
            e.preventDefault();
            const touches = e.targetTouches;
            for (let i = 0; i < touches.length; i++) {
                if (i >= pointers.length) pointers.push(new pointerPrototype());

                pointers[i].id = touches[i].identifier;
                pointers[i].down = true;
                pointers[i].x = touches[i].pageX;
                pointers[i].y = touches[i].pageY;
                pointers[i].color = [
                    Math.random() + 0.2,
                    Math.random() + 0.2,
                    Math.random() + 0.2,
                ];
            }
        });

        window.addEventListener("mouseleave", () => {
            pointers[0].down = false;
        });

        window.addEventListener("touchend", (e) => {
            const touches = e.changedTouches;
            for (let i = 0; i < touches.length; i++)
                for (let j = 0; j < pointers.length; j++)
                    if (touches[i].identifier == pointers[j].id) pointers[j].down = false;
        });

        window.addEventListener("scroll", handleScrollHeight);
    });

    onBeforeUnmount(() => {
        window.removeEventListener("scroll", handleScrollHeight);
    });
}

// 头部笑脸特效
export const usePortrait = () => {
    onMounted(() => {
        document.querySelector("body").addEventListener("mousemove", eyeball);
        function eyeball() {
            var eye = document.querySelectorAll(".eye");
            eye.forEach(function (eye) {
                let x = eye.getBoundingClientRect().left + eye.clientWidth / 2;
                let y = eye.getBoundingClientRect().top + eye.clientHeight / 2;
                let radian = Math.atan2(event.pageX - x, event.pageY - y);
                let rot = radian * (180 / Math.PI) * -1 + 270;
                eye.style.transform = "rotate(" + rot + "deg)";
            });
        }
    });
}